[Pxr] Add CMake dependency lookups for python modules.

This adds a PyOpenGL lookup module, makes the dependency
in usdview explicit and does the same for jinja2 and usdGenSchema.

Fixes #91

(Internal change: 1669990)

cmake/defaults/Packages.cmake

@@ -89,11 +89,12 @@ if (PXR_BUILD_IMAGING)
     find_package(X11)
     # --PySide
     find_package(PySide)
+    # --PyOpenGL
+    find_package(PyOpenGL)
 endif()
 
 # Third Party Plugin Package Requirements
 # ----------------------------------------------
-
 if (PXR_BUILD_KATANA_PLUGIN)
     find_package(KatanaAPI REQUIRED)
     find_package(Boost

cmake/modules/FindJinja2.cmake

@@ -21,8 +21,6 @@
 # KIND, either express or implied. See the Apache License for the specific
 # language governing permissions and limitations under the Apache License.
 #
-# - Find Modo libraries
-#
 # Jinja2 is a python library, ensure that it is available for use with our
 # specified version of Python.
 #
@@ -37,6 +35,7 @@ execute_process(
         jinja2ImportResult 
 )
 if (jinja2ImportResult EQUAL 0)
+    message(STATUS "Found Jinja2")
     set(JINJA2_FOUND True)
 endif()
 

cmake/modules/FindPyOpenGL.cmake

@@ -0,0 +1,41 @@
+#
+# Copyright 2016 Pixar
+#
+# Licensed under the Apache License, Version 2.0 (the "Apache License")
+# with the following modification; you may not use this file except in
+# compliance with the Apache License and the following modification to it:
+# Section 6. Trademarks. is deleted and replaced with:
+#
+# 6. Trademarks. This License does not grant permission to use the trade
+#    names, trademarks, service marks, or product names of the Licensor
+#    and its affiliates, except as required to comply with Section 4(c) of
+#    the License and to reproduce the content of the NOTICE file.
+#
+# You may obtain a copy of the Apache License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the Apache License with the above modification is
+# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied. See the Apache License for the specific
+# language governing permissions and limitations under the Apache License.
+#
+# PyOpenGL is a python library, ensure that it is available for use with our
+# specified version of Python.
+#
+
+if (NOT PYTHON_EXECUTABLE)
+    return()
+endif()
+
+execute_process(
+    COMMAND 
+        "${PYTHON_EXECUTABLE}" "-c" "from OpenGL import *"
+    RESULT_VARIABLE
+        pyopenglImportResult 
+)
+if (pyopenglImportResult EQUAL 0)
+    message(STATUS "Found PyOpenGL")
+    set(PYOPENGL_FOUND True)
+endif()

pxr/usd/lib/usd/CMakeLists.txt

@@ -113,6 +113,10 @@ pxr_shared_library(usd
         generatedSchema.usda
 )
 
-pxr_python_bins(
-    usdGenSchema
-)
+if (NOT JINJA2_FOUND)
+    message(WARNING "Skipping building usdGenSchema due to missing dependency: Jinja2")
+else()
+    pxr_python_bins(
+        usdGenSchema
+    )
+endif()

pxr/usdImaging/lib/usdviewq/CMakeLists.txt

@@ -4,6 +4,9 @@ set(PXR_PACKAGE usdviewq)
 if (NOT PYSIDE_FOUND)
     message(WARNING "Not building ${PXR_PACKAGE} because of missing dependency: PySide")
     return()
+elseif(NOT PYOPENGL_FOUND)
+    message(WARNING "Not building ${PXR_PACKAGE} because of missing dependency: PyOpenGL")
+    return()
 endif()
 
 pxr_shared_library(usdviewq